Metal amides are useful as precursor compounds for chemical vapor deposition; see, e.g., U.S. Pat. Nos. 5,178,911; 5,417,823; and 6,080,446. Metal amides are also useful in the synthesis of polymerization catalysts; see, e.g., U.S. Pat. No. 6,020,444. Metal amides are also useful in formation of metal-rich layers on materials having high dielectric constants, such as are used in construction of microelectronic devices; see, e.g., WO 02/27063.
Known processes for making metal amides require the transfer of a solid transition metal salt to a slurry of a lithium alkylamide. See, e.g., D. C. Bradley and I. M. Thomas, J. Chem. Soc., 1960, 3857-3861. The addition of solids into a reaction vessel with a reactive reagent present is a difficult and potentially hazardous operation on commercial scale since the flow is hard to control. The reverse reaction (i.e., adding a lithium amide to a metal halide slurry) is also possible, however the lithium amide salts are usually of low solubility and slurries of these salts tend to be nonhomogeneous, thick and difficult to completely transfer, and thus reaction stoichiometry cannot be adequately controlled to provide metal amides of commercially acceptable quality and quantity.
Accordingly, there is a need for improved synthetic routes for metal amides.